My webcam isn't working. What's the first thing I should check?

The most common reasons for a webcam not working are simple ones.

1.) Ensure the webcam is properly connected to your computer (if it's external, check the USB port; if it's internal, ensure no physical obstructions or privacy shutters are engaged).

2.) Check your privacy settings within your operating system (e.g., Windows Privacy settings, macOS Security & Privacy) to ensure applications are allowed to access the camera. 

3.) Try restarting your computer; this can often resolve temporary software glitches.